Ultrasonic sealer

ABSTRACT

An ultrasonic sealing apparatus comprises at least one horn having an elongated sealing face for sealing a packing material. Plural converters are erected on a side of the horn opposite to the sealing face for resonating the horn with a vibrating frequency. The ultrasonic sealing apparatus has a length that is one wavelength of the vibrating frequency and is fixed in position to a sealing jaw at a nodal plane of the vibrating frequency.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to an ultrasonic sealing apparatusprovided with an elongated sealing face for sealing a packing material,specifically a tubular packing material filled with content such as aliquid beverage, and more particularly to an ultrasonic sealingapparatus having at least one horn and plural converters and to atransverse sealing apparatus provided with the ultrasonic sealingapparatus.

2. Background Art

Hitherto, there has been known a packing machine in which a sterilizedpacking material web is used for a rectangular parallelepiped packingcontainer filled with juice, etc. as shown in FIG. 1 see also (JapanesePatent Publication No. 23368/1989). In brief, the filling/packingmachine as a whole comprises a reel 2 supporting a packing material web1 in a rolled state, a sterilization, device 3 for sterilizing thetabular packing material web successively unwound from the reel 2, alongitudinal sealing section 4 for sealing the longitudinal edges of thesterilized packing material web and thereby forming a tubular packingmaterial web, a liquid supply tube 5 for filling a fluid content intothe tubular form, a transverse sealing device 7 for sealing the tubularpacking material web in a direction perpendicular to the longitudinaldirection thereof while feeding downward the tube filled with thecontent by a length substantially corresponding to one container and, atthe same time, continuously forming pillow-shaped containers 6 which arerectangle in section, and a container shaping device 8 for forming thepillow-shaped containers 6 into rectangular parallelepiped containerswhich are the final form by folding its end portions. Theabove-mentioned transverse sealing device 7 is composed of a sealingunit, a sealing jaw for fixing the said sealing unit, and a drivingmeans for driving the said sealing jaw.

The following ultrasonic sealing apparatuses are known.

Japanese Laid-Open Patent Application No. 2231/1995 discloses anultrasonic sealing apparatus which comprises a piezoelectric drivingunit having a piezoelectric ceramic plate or a magnetostriction drivingunit, which is connected to an AC supply source, and a horn having anelongated sealing surface, and which is further characterized with oneor more reaction bodies forming a half wavelength together with thehorn.

Japanese Patent Publication No. 22784/1987 discloses an ultrasonicwelding apparatus for a container body comprising a longitudinal grooveon the center line of a butting face which has a substantiallyrectangular form in a side sealing portion of an ultrasonic weldinghorn, wherein the horn includes steps with small differences providedtoward the center of both side faces of the longitudinal groove for sidesealing by ultrasound a container body of card board laminated withplastic film.

Japanese Patent Publication No. 2544450 discloses a hermetic sealingmethod for sealing a paper container for liquid characterized in thatthe method for sealing the open end portions of a container having athermoplastic layer on its paper surface comprises sealing the upper andlower portions of the tubular body by affixing each end portion of onesheet, whereby an entire face of the open end to be sealed issimultaneously heated in an oven and subsequently preparatively sealedby applying pressure, and finally ultrasonically sealed.

Japanese Model Laid-Open Application No. 147408/1988 discloses anultrasonic sealing apparatus for liquid containers, wherein aband-shaped ridge is provided nearly at the center of a face of the hornbutting against a portion to be sealed, a concave groove perpendicularto the ridge is provided nearly at the center of a face of the anvilbutting against the portion to be sealed, a bottom portion of theconcave groove is made into a two-step structure and its step portionand both end portions are tapered, and an acute-shaped protruded slantface extending sideward is provided at an end portion of the center ofthe bottom portion on the ultrasonic sealing apparatus for sealing upperand lower open end portions of a tubular liquid container, which isrectangular in section, having an overlapping bonded portion nearly at acenter of a body consisting of a horn and an anvil.

Japanese Laid-Open Patent Application No. 501543/1987 corresponding to(PCT/US85/02564) discloses an ultrasonic horn apparatus used fordissolving reagent tablets in a cuvette, comprising a horn body, whichis generally a rectangular horn body, having a front end face and a rearend face, for transmitting acoustic waves substantially at a right angleto the front end face to interact with a content in the cuvette whichmoves in the vicinity of the front end face, in response to vibrationsapplied to the rear end face, a converter means fixed to the rear endface of the horn body at the center position in the direction of thewidth of the rear end face for applying the vibrations to the horn bodyin response to electrical energy supplied to the converter means, and apair of resonating members each having an acoustic length equal to ahalf wave length of the acoustic waves transmitted from the horn bodyand fixed to the end regions in the direction of width of the rear endface and extending at a right angle from the rear end face, for causingacoustic waves transmitted nearly at a right angle from the front endface to propagate at a nearly uniform amplitude along the direction ofwidth of the front end face, wherein the content in the cuvette movingalong the direction of width of the front end face at a certain distancefrom the front end face is subjected to nearly uniform acoustic waves.

Japanese Laid-Open Patent Application No. 33121/1995 discloses a sealingapparatus for packing containers comprising an anvil supporting packingmaterials for the packing containers on whose surface a sealant layer isformed, a horn transmitting ultrasonic vibrations to packing materialsby applying pressure pressing the packing materials against the anvil,and an ultrasonic vibration absorbing means provided between, the tipend of the horn and the edge portion of the packing material, so thatthe horn transmits the ultrasonic vibration to the packing materials,and is able to weld sealant layers to each other, while preventing aside of the edge portion of the packing materials from being excited,and accordingly preventing dust from occurring at the end surfaces ofthe paper substrates exposed at the edge portions of the packingmaterials.

Japanese Laid-Open Patent Application No. 92046/1981 discloses anultrasonic sealing machine comprising an ultrasonic welding apparatusfor a container body comprising a horn including steps at one side edgeof a sealing face facing the sealing portion of the horn, wherein thesteps are open at the portions corresponding to the vicinity of the topend of the sealing portion for side sealing paper containers of aplastic film laminate and the like.

Japanese Laid-Open Patent Application No. 15741/1994 discloses anultrasonic sealing apparatus for manufacturing packing containers fromthermoplastic materials, comprising a giant magnetostrictive powdercomposite (GMPC) made of magnetostrictive materials, and wherein thevibration generator is wound around by a coil generating a magneticfield and secured on to a sealing jaw, and has a cross sectional areawhich progressively reduces when seen from an anchorage point againstthe jaw, and a free face of an end portion is provided on a narrowsurface.

U.S. Pat. No. 5,730,351 discloses a device for ultrasonic treatment of aworkpiece, the device comprising a horn (sonotrode) having a first sideand a second side both contacting the workpiece; and a drive unit forthe horn, whereby the drive unit includes first and second ultrasoundoscillating units, and first and second connecting means arranged spacedapart for individually connecting the first and second oscillation unitsrespectively to said second face of the horn.

Japanese Laid-Open Patent Application No. 128237/1998 discloses anultrasonic apparatus for supplying vibratory energy in the ultrasonicfrequency range to a workpiece, the ultrasonic apparatus comprising ahorn whose dimension is set to mechanically resonate at a predeterminedfrequency in the ultrasonic frequency range, plural to piezoelectrictransducers coupled to the horn for causing the horn to resonate at saidpredetermined frequency, a power supply connected to the transducers forproviding electrical energy at the predetermined frequency to saidtransducers and causing said transducers to be energized in parallel,and a means for balancing the electrical current flow through thetransducers coupled to the circuit between the power supply and eachtransducer.

At present, a packing material comprising a laminate of paper, aluminumfoil and thermoplastic is mainly used for one-use disposable packingcontainers having a rectangular parallelpiped shape filled with a liquidsuch as juice and closed in a sealed manner. In the future it isconsidered that a packing container using a packing material comprisinga laminate of thermoplastic having no aluminum foil will be themainstream, since recycling treatment of packing material laminateincluding aluminum foil is considered difficult after containers aredisposed. However, for heat sealing a packing material comprising alaminate of thermoplastic including no aluminum foil, a heat sealingapparatus using a high-frequency coil which has been used with packingmaterials including aluminum foil cannot be applied, so it is necessaryto use other heat sealing apparatuses such as an ultrasonic sealingapparatus, for example.

Generally, an ultrasonic sealing apparatus includes a converter, abooster and a horn. The electrical vibration is converted intomechanical vibration by a converter, and the booster is used to fix theapparatus mechanically and to amplify the amplitude of the vibration.The horn further amplifies the amplitude so that the desired sealingsurface is formed. However, the ultrasonic sealing apparatuses, whichhave well-known properties and which have been generally used, require alarger space for the apparatus when enhancing the heat sealing abilityand there is a drawback that such apparatus cannot be set on a sealingjaw of a transverse sealing apparatus of the filling/packing machine.For practical use, there is a need for an ultrasonic sealing apparatuscapable of outputting high power while occupying a much smaller space,and which can be applied to a transverse sealing apparatus.

Additionally, uniformly heat sealing the elongated entire face at bothend portions has been considered difficult with the known ultrasonicapparatuses used for a sealing jaw of the transverse sealing apparatusof a filling/packing machine, because one converter is used and thedimension of the motional amplitude at the sealing face of the horn(output surface) reduces with increasing lateral distance away from thecentral area where the converter is coupled to the horn.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an ultrasonic sealingapparatus which can be set on a sealing jaw of a transverse sealingapparatus of a filling/packing machine for effecting a transversesealing of an appropriate length, and in particular an elongated uniformheat sealing, and wherein the ultrasonic sealing apparatus is compactand able to output larger power.

The inventors of the present invention have made a keen investigationand have solved the above object by provision of an ultrasonic sealingapparatus comprising one horn having an elongated sealing face forsealing a packing material and plural converters erected on the horn,and one or more fixtures provided parallel to the converter, wherein thefixing position at the fixture of the ultrasonic sealing apparatus andthe sealing jaw is a nodal plane farther (i.e. remote) from the sealingface. According to a further aspect of the invention, there is providedan ultrasonic sealing apparatus comprising one horn and pluralconverters, wherein the horn has an attaching flange for fixing theultrasonic sealing apparatus to the sealing jaw and the attaching flangewhich becomes the fixing position of the ultrasonic sealing apparatusand the sealing jaw is a nodal plane closer to the sealing face. Sucharrangements make possible an elongated uniform heat seal, while at thesame time provide ultrasonic sealing apparatuses that are compact andable to output large power, and can be set on the sealing jaw of atransverse sealing apparatus of a filling/packing machine.

Stated another way, the present invention relates to an ultrasonicsealing apparatus, comprising at least one horn having an elongatedsealing face for sealing a packing material and plural converterserected on a side opposite to the sealing face of the horn, whichresonates the horn, and the length of the ultrasonic sealing apparatusis a length of one wavelength and its fixing position to the sealing jawis a nodal plane.

Additionally, the present invention relates to the above-mentionedultrasonic sealing apparatus wherein the ultrasonic sealing apparatushas one or more fixtures erected on a side opposite to the sealing faceof the horn for fixing the ultrasonic sealing apparatus to the sealingjaw wherein the fixing position of the ultrasonic sealing apparatus andthe sealing jaw in the fixtures is a nodal plane farther from thesealing face.

Further, the present invention relates to the above-mentioned ultrasonicsealing apparatus wherein the fixture has a receiving face of attachmentfor fixing the ultrasonic sealing apparatus to the sealing jaw, and thereceiving face of attachment which becomes the fixing position of theultrasonic sealing apparatus and the sealing jaw is a nodal planefarther from the sealing face.

Further, the present invention relates to the above-mentioned ultrasonicsealing apparatus wherein the fixture has a female screw portion forfixing the ultrasonic sealing apparatus to the sealing jaw using a screwconnection.

Further, the present invention relates to the above-mentioned ultrasonicsealing apparatus wherein the fixture has a collar for fixing theultrasonic sealing apparatus to the sealing jaw, and the collar whichbecomes the fixing position of the ultrasonic sealing apparatus and thesealing jaw is a nodal plane farther from the sealing face.

Further, the present invention relates to the above-mentioned ultrasonicsealing apparatus wherein the fixture has a screw portion to be fixed tothe horn using a screw connection.

Further, the present invention relates to the above-mentioned ultrasonicsealing apparatus wherein the fixture is formed uninterruptedly with thehorn.

Further, the present invention relates to the above-mentioned ultrasonicsealing apparatus wherein the horn has an attaching flange for fixingthe ultrasonic sealing apparatus to the sealing jaw, and the attachingflange which becomes the fixing position of the ultrasonic sealingapparatus and the sealing jaw on the horn is a nodal plane closer to thesealing face.

Further, the present invention relates to the above-mentioned ultrasonicsealing apparatus wherein the horn has a slot and/or slit to reduceunwanted vibrations.

Further, the present invention relates to the above-mentioned ultrasonicsealing apparatus wherein the horn is made of a material having a sonicspeed for longitudinal waves at or below 4,000 m/s.

Further, the present invention relates to the above-mentioned ultrasonicsealing apparatus wherein the material having a sonic speed forlongitudinal waves at or below 4,000 m/s is a copper alloy.

Further, the present invention relates to the above-mentioned ultrasonicsealing apparatus wherein the copper alloy is phosphorous bronze.

Further, the present invention relates to the above-mentioned ultrasonicsealing apparatus wherein the converter has a screw portion to be fixedto the horn or to the fixture using screw connection.

Further, the present invention relates to the above-mentioned ultrasonicsealing apparatus wherein the plural converters have a control means inorder to obtain a uniform and suitably strong seal at the sealing face.

Further, the present invention relates to the above-mentioned ultrasonicsealing apparatus wherein the screw connection is a screw connectionusing a stud bolt.

Further, the present invention relates to the above-mentioned ultrasonicsealing apparatus wherein the sealing face has a ridge in thelongitudinal direction of the sealing face successively orintermittently.

Further, the present invention relates to the above-mentioned ultrasonicsealing apparatus wherein the frequency ranges from 20 KHz to 60 KHz.

Further, the present invention relates to the above-mentioned ultrasonicsealing apparatus wherein the frequency is 40 KHz.

Further, the present invention relates to the above-mentioned ultrasonicsealing apparatus, which includes a plurality of the above-mentionedultrasonic sealing apparatuses.

Still further, the present invention relates to a transverse sealingapparatus comprising the above-mentioned ultrasonic sealing apparatusand the sealing jaw to which the ultrasonic sealing apparatus is fixedand a driving means for the sealing jaw.

Further, the present invention relates to the above-mentioned transversesealing apparatus wherein the sealing jaw has a damper member for thehorn.

The ultrasonic sealing apparatus of the present invention comprises atleast one horn having an elongated sealing face for sealing a packingmaterial and plural converters erected on a side opposite to the sealingface of the horn which resonate the horn, and which is characterized inthat the length of the ultrasonic sealing apparatus is a length of onewavelength and whose fixing position to the sealing jaw is a nodalplane. And more particularly this ultrasonic sealing apparatus ischaracterized in that it comprises one horn having an elongated sealingface for sealing a packing material, plural converters erected on thehorn and one or more fixtures provided in parallel to, the converters,wherein the converters resonating the horn or the; fixture fixing theultrasonic sealing apparatus to the sealing jaw forms the length of onewavelength with the horn, and the fixing position of the ultrasonicsealing apparatus and the sealing jaw in the fixture is a nodal planefarther from the sealing face. And generally, the ultrasonic sealingapparatus of the invention is fixed on a sealing jaw of a transversesealing apparatus of a filling/packing machine for heat sealing apacking material. According to a further aspect of the invention, thetransverse sealing apparatus of the present invention comprises anultrasonic sealing apparatus, a sealing jaw to which the ultrasonicsealing apparatus is fixed, and a driving means for the sealing jaw.

Any tabular material may be used as the packing material in the presentinvention, so long as the material can be formed into a container or thelike, and the materials have a heat-welding layer such as polyethyleneon at least one of front and back sides of a paper or a barrier resin aswell as materials having an intermediate layer such as aluminum foil andan adhesive layer on said one side. For example, a packing material webfor a filling and packing container of a juice or the like, is composedas a heat-welding layer such as polyethylene provided on the outermostlayer surface of front and back faces of a paper which is a basematerial, and a barrier layer or an adhesive layer and the like of anintermediate layer of aluminum foil or barrier resin is provided as theneed arises. Usually a thickness of 170 to 900 μm is adopted for thethickness of the web. Additionally, it is necessary to use materialswhich can welded by ultrasound for the innermost layer surfacecontacting the liquid content.

The ultrasonic sealing apparatus of the invention is, an apparatuscapable of heat-sealing by heat dissolving and applying pressure byconverting an electrical vibration frequency of 20 kHz or higher into amechanical vibration, delivering an ultrasonic vibration to a heatadhesive part from the resonator which is called a horn, for generatinga high frictional heat on the border surface. With a motional amplitudeof approximately 15 to 70 μm and a vibration frequency of approximately20,000 to 60,000 times per second, heat is generated in an extremelyshort time. Thus, an ultrasonic heat-sealing may be regarded as sealingby internal heat as well as sealing using high-frequency.

Any horn may be used as the horn of the ultrasonic sealing apparatus inthe present invention, so long as it is able to weld sealing layers ofthe packing material with each other by transmitting ultrasonicvibrations. An exemplary horn includes an elongated sealing faceprovided on its tip, a curved portion having a curved shape such as atapered shape, exponential shape or hanging-down shape toward thesealing face, and a flat face portion on a side opposite to the sealingface. On the flat face portion on the side opposite to the sealing face,plural converters and one or more fixtures are erected. Further, it ispossible to form the horn and the fixtures uninterruptedly on whichuninterrupted body plural converters may be erected. On the other hand,on the sealing face of the horn or the anvil, it is possible to providea ridge having a round or rectangular shape in its section in thelongitudinal direction of the sealing face continuously orintermittently.

Additionally it is desirable to use a horn having a slot (a penetratedand elongated hole provided in the direction of thickness) and/or slit(an elongated groove provided in the longitudinal direction) to reduceunwanted vibrations. And generally the slot is provided below theconverters and the fixtures, while the slit is provided below betweenthe converters, or below and between the converters and the fixtures.Also in the present invention, it is possible to provide an attachingflange on the horn for fixing the ultrasonic sealing apparatus to thesealing jaw. It is also possible to make the attaching flange as afixing position of the ultrasonic sealing apparatus and the sealing jaw,and as a nodal plane closer to the sealing face.

As a horn material, it is possible to utilize ceramics in addition to,metals or alloys such as copper alloys, aluminum or aluminum alloys,titanium or titanium alloys. And when the frequency is fixed, as thelength of the horn is in proportion to the sonic speed of the material,from the viewpoint of making an ultrasonic sealing apparatus withsmaller dimension, it is desirable to use a horn material having a slowsonic speed of longitudinal waves, for example, of 4,000 m/s or lower.Exemplary materials having a sonic speed of longitudinal waves of 4,000m/s or lower include copper alloys such as phosphorous bronze (3,360m/s), beryllium bronze (3,780 m/s) and Nepal brass (3,240 m/s), orpiezoelectric ceramic materials PZT (3,000 m/s) may be utilized. Inaddition, depending on the structure of the transverse sealingapparatus, or in the case that downsizing the apparatus is not required,light metals or light metal alloys and the like whose sonic speed oflongitudinal waves is 4,000 m/s and above, such as aluminum or aluminumalloys, titanium or titanium alloys and the like, may also be used asthe need arises.

As mentioned above, the horn is used to apply pressure by pressing apacking material against the anvil with the sealing face provided on thetip of the horn, then to transmit vibratory energy (ultrasonicvibration) concentrated at the tip to heat the adhesive portion of thepacking material, thus generating a large frictional heat on the bordersurface with which the adhesive portion is dissolved by heat. Thepacking material is thus heat-sealed in cooperation with pressure. Whilethe structure and materials of the anvil are not specially limited, theanvil may by made of, for example, a stainless steel material.

Any converter, including electrostrictive and magnetostrictive, may beused for the converters in an ultrasonic sealing apparatus of thepresent invention, so long as the converter converts the electricalvibration of the vibratory generator to a mechanical vibration andresonates the horn; however, an electrostrictive converter ispreferable. In such case, an electrostrictive piezoelectric elementusing ceramic materials is desirable. Converters of this kind convertthe supplied voltage to a mechanical strain, the energy of which strainis supplied to the horn as ultrasonic vibrations. In the ultrasonicsealing apparatus of the present invention, it is necessary to provideplural converters, preferably 2 to 5 converters, in order to obtain anexcellent seal.

Converters in the present invention are erected on the side of the hornopposite to the sealing face of the horn. This is achieved by fixing theconverters to a flat face portion on the side opposite to the sealingface of the horn or to the flat face portion of the fixture which isfixed to the flat face portion, or by fixing the converters to the flatface portion of the fixture which is formed uninterruptedly with thehorn. This fixing may be done by any fixing means so long as it fixesthe horn to the converters firmly, while in order to make an ultrasonicsealing apparatus of the present invention with smaller dimension, it isdesirable to fix the converters on the horn by a screw connection,specifically by using a stud bolt, for which a female bolt portion isprovided on the horn side of the converters.

Further, each converter is connected to a power supply of alternatingcurrent and it is desirable to provide a control means in order totransmit the vibratory energy from the plural converters uniformly tothe sealing face of the horn in order to obtain a seal with uniform andsuitable strength on the sealing face. Without a control means, thevibration becomes non-uniform and there is a possibility that a sealwith uniform and suitable strength on the sealing face will not be,obtained. The control means may be implemented by a balancingtransformer as described in Japanese Laid-Open Patent Application No.128237/1998.

Any fixture may be used in the ultrasonic sealing apparatus in thepresent invention so long as it fixes the ultrasonic sealing apparatusto the sealing jaw whereby the fixing position, or the vicinity of thefixing position, of the ultrasonic sealing apparatus and the sealing jawforms a nodal plane farther from the sealing face, and one or more ofthem are erected on the side opposite to the sealing face of the horn,for example, on the flat face portion of the opposite side. When appliedto a transverse sealing apparatus of a filling/packing machine, it isnecessary that the ultrasonic sealing apparatus be attached and fixed tothe sealing jaw in a compact manner. Accordingly, it is preferable toattach compactly by means of a screw connection using a stud bolt or thelike, which is described in the following, rather than fixing theultrasonic sealing apparatus by providing a flange on the sealing jawand using the same. On the other hand, for fixing the fixture with thehorn, it is preferable to fix compactly by means of a screw connectionusing a stud bolt and the like. Additionally, it is also possible toform the fixture and the horn together uninterruptedly asaforementioned, or fix a formed body in which a plurality of erectedfixtures are coupled in their lower parts to the above-mentioned flatface portion of the horn by screw connection using a stud bolt and thelike. The cross-sectional form of the fixture in the present inventionmay be exemplified as a round or rectangular shape.

Fixing the ultrasonic sealing apparatus to the sealing jaw can beachieved, for example, at the end portion of the fixture on the sideopposite to the horn or at the center portion of the fixture. When fixedat the end portion of the fixture on the side opposite to the horn, anattachment method such as stud attachment and the like for fixing theultrasonic sealing apparatus to the sealing jaw is used, for which afemale screw portion is used as a fixture. In this case, a female screwportion hole is provided so that a receiving face of the attachmentwhich becomes the fixing position in the fixture is a nodal planefarther from the sealing face. Also, when fixed at the central portionof the fixture, the ultrasonic sealing apparatus is fixed to the sealingjaw by properly coupling a collar provided at the central portion of thefixture with the sealing jaw. In this case, the position of the collaris determined so that the collar-provided portion becomes a nodal planefarther from the sealing face. Further, fixing the ultrasonic sealingapparatus to the sealing jaw, as aforementioned, is achieved byproviding an attaching flange on the horn for fixing the ultrasonicsealing apparatus to the sealing jaw. In this case, this attachingflange becomes a fixing position of the ultrasonic sealing apparatus andthe sealing jaw as well as a nodal plane closer to the fixing position.

The position of the nodal plane can be set precisely by a vibrationanalysis and the like using a computer at the stage of designingfixtures or horns.

In an ultrasonic sealing apparatus of the present invention, there existtwo nodal planes because the entire length of the apparatus isconstituted of one wavelength of the vibrating frequency. The ultrasonicsealing apparatus of the present invention is characterized in thateither nodal plane of the two nodal planes present, one being closer toand the other farther from the sealing face, becomes the fixing positionof the ultrasonic sealing apparatus and the sealing jaw. Additionally,when the nodal plane farther from the sealing face becomes the fixingposition, it, is preferable to provide a damper member at the side frameof the sealing jaw, using the nodal plane closer to the sealing face,for preventing the horn of the ultrasonic sealing apparatus, which isrotating at a high speed, from swinging, and for making the sealing faceof the horn butt precisely to the position of a packing material to besealed.

Further, the ultrasonic sealing is performed at a frequency of 20 KHz to60 KHz, preferably at 40 KHz with the general output at the extent of 2KW, while the entire length of the apparatus including the converters orthe fixture and the horn is set to correspond to the length of onewavelength. In such case, the amplitude at the sealing face of the tipend portion of the horn becomes maximum so that the exothermicefficiency is enhanced, thus enlarging the sealing strength. Forexample, for a horn material with slow sonic speed comprising a materialwhose sonic speed of the longitudinal wave is 3,600 m/s at a frequencyof 40 KHz, the length of one wavelength is 9 cm. In this case, theentire length of the apparatus including the converters, or the fixtureand the horn is 9 cm to make the length of the converters, the fixtureand the horn be 4.5 cm respectively. Therefore, when the entire lengthof the ultrasonic sealing apparatus is to the extent of 10 cm, it ispossible to be used as a transverse sealing apparatus for thefilling/packing machine of the prior art.

Moreover, when the traversing face is long as in the case of a largecontainer and a long sealing surface is required, it is possible toenlarge the sealing face by connecting a plurality of the abovedescribed ultrasonic sealing apparatuses. Additionally, an ultrasonicsealing apparatus of the present invention may or may not have a boosterwhich is used to amplify the amplitude.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an entire view of the filling/packing machine in which anultrasonic sealing apparatus of the present invention is applied.

FIG. 2 is a schematic perspective view of an ultrasonic sealingapparatus of the present invention.

FIG. 3 is a schematic perspective view of an ultrasonic sealingapparatus of another mode of the present invention.

FIG. 4 is a schematic front view of an ultrasonic sealing apparatus ofanother mode of the present invention.

FIG. 5 is a schematic front view of an ultrasonic sealing apparatus ofanother mode of the present invention.

FIG. 6 is a schematic front view of an ultrasonic sealing apparatus ofthe present invention shown in FIG. 2.

FIG. 7 is a schematic front view of horns of various shapes in anultrasonic sealing apparatus of the present invention.

FIG. 8 is a schematic side view of horns of various shapes in anultrasonic sealing apparatus of the present invention.

FIG. 9 is a schematic perspective view of an ultrasonic sealingapparatus of another mode of the present invention.

BEST MODES TO CARRY OUT THE INVENTION

The preferable examples of embodiments of an ultrasonic sealingapparatus of the present invention are described according to thedrawings in the following, while the present invention is not limited tothe description in the drawings.

FIG. 2 is a schematic perspective view of an ultrasonic sealingapparatus 10 of the present invention. Additionally, in FIG. 2 to FIGS.9, 10 shows an which includes a horn 11; a converter 12; a fixture 13; ahorn-fixture uninterruptedly formed body 14; a sealing face 15 of thehorn 11; a flat face 16 of the horn 11; a curved portion 17 of the horn11; a slot 18; a slit 19; a collar 20; a stud bolt 21; a receiving face22 of stud attachment; a female screw portion 23; a sealing jaw 24; adamper fixing 25; a nodal plane 26; a stud attachment 27; and anattaching flange 28, respectively.

With reference to FIG. 2, the ultrasonic sealing apparatus 10 of thepresent invention is shown in which two converters 12 and three fixtures13 are erected on the horn 11 having the sealing face 15, the flat face16, the curved portion 17 and the slot 18. In this apparatus 10, thefemale screw portion 23 for fixing the apparatus to the horn 11 using astud bolt 21 is provided on the converters 12 and the fixtures 13. Also,the female screw portion 23 for fixing the apparatus with the sealingjaw using a stud attachment 27 is provided on the fixtures 13.

FIG. 3 shows an ultrasonic sealing apparatus 10 of the present inventionin which two converters 12 are erected on the horn-fixtureuninterruptedly formed body 14 by forming the horn 11 and the fixtures13 together uninterruptedly. In this apparatus 10, likewise theapparatus 10 shown in FIG. 2, the receiving face of stud attachment 22becomes an attaching position constituting a nodal plane 26 farther fromthe sealing face 15.

FIG. 4 shows an ultrasonic sealing apparatus 10 of the present inventionin which two fixtures 13 are erected next to the horn 11 between twoconverters 12 at both exterior sides, by which two fixtures 13, theultrasonic sealing apparatus 10 is fixed to the sealing jaw 24 and alsoin this case, the receiving face of stud attachment 22 is a nodal plane26 farther from the sealing face 15.

FIG. 5 shows an ultrasonic sealing apparatus 10 of the present inventionin which one fixture 13 is erected next to the horn 11 between twoconverters 12 at both exterior sides and in this apparatus 10, thecollar 20 provided at the center portion of the fixtures 13 to fix theapparatus to the sealing jaw 24 becomes an attaching position and anodal plane 26 farther from the sealing face 15.

FIG. 6 shows a state in which the ultrasonic sealing apparatus 10 shownin FIG. 2 is fixed to the sealing jaw 24 and a hexagonal-holed bolt 21which can be embedded in the sealing jaw 24 is used for fixing thefixtures 13. Further aforementioned, also in this case the receivingface 22 of stud attachment 27 becomes the fixing position and a nodalplane 26 farther from the sealing face 15. Also, the damper fixing bolt25 is provided on the side frame of the sealing jaw 24, to prevent thehorn from swinging at the curved portion 17 of the horn which becomes anodal plane closer to the sealing face 15. FIG. 6 also shows thepillow-shaped container 6 which is to be sealed.

Additionally, FIGS. 7 and 8 show the horns 17 of various shapes havingthe sealing face 15, the flat face portion 16 and the curved portion 17,and the slot 18 or the slit 19.

FIG. 9 shows the ultrasonic sealing apparatus in which the attachingflange for fixing the ultrasonic sealing apparatus to the sealing jaw isprovided on the horn. In this case, the attaching flange becomes thefixing position of the ultrasonic sealing apparatus and a nodal planecloser to the sealing face.

Industrial Applicability

The present invention makes it possible to provide a smaller ultrasonicsealing apparatus with larger pressure power and enhanced sealingcapability compared to the ultrasonic sealing apparatuses of the priorart, and furthermore is capable of uniformly sealing an elongatedsealing face.

What is claimed is:
 1. An ultrasonic sealing apparatus, comprising: atleast one horn having an elongated sealing face for sealing a packingmaterial: and plural converters erected on a side of the horn oppositeto the sealing face for resonating the horn with a vibrating frequency,wherein the ultrasonic sealing apparatus has a length that is onewavelength of the vibrating frequency and which is fixed in position toa sealing jaw at a nodal plane of the vibrating frequency.
 2. Theultrasonic sealing apparatus according to claim 1, including at leastone fixture erected on a side opposite to the sealing face of the hornfor fixing the ultrasonic sealing apparatus to the sealing jaw, and thefixing position of the ultrasonic sealing apparatus and the sealing jawis a nodal plane remote from the sealing face.
 3. The ultrasonic sealingapparatus according to claim 2, wherein the fixture has a receiving faceof attachment for fixing the ultrasonic sealing apparatus to the sealingjaw, and the receiving face of attachment which becomes the fixingposition of the ultrasonic sealing apparatus and the sealing jaw is anodal plane remote from the sealing face.
 4. The ultrasonic sealingapparatus according to claim 2, wherein the fixture has a female screwportion for fixing the ultrasonic sealing apparatus to the sealing jawusing a screw connection.
 5. The ultrasonic sealing apparatus accordingto claim 2, wherein the fixture has a collar for fixing the ultrasonicsealing apparatus to the sealing jaw, the collar constituting the fixingposition of the ultrasonic sealing apparatus and the sealing jaw andbeing at a nodal a plane remote from the sealing face.
 6. The ultrasonicsealing apparatus according to claim 2, wherein the fixture has a screwportion fixable to the horn using a screw connection.
 7. The ultrasonicsealing apparatus according to claim 2, wherein the fixture is formeduninterruptedly with the horn.
 8. The ultrasonic sealing apparatusaccording to claim 1, wherein the horn has an attaching flange forfixing the ultrasonic sealing apparatus to the sealing jaw, theattaching flange constituting the fixing position of the ultrasonicsealing apparatus and the sealing jaw on the horn and being at a nodalplane close to the sealing face.
 9. The ultrasonic sealing apparatusaccording to claim 1, wherein the horn includes at least one of a slotand a slit to reduce unwanted vibrations.
 10. The ultrasonic sealingapparatus according to claim 1, wherein the horn comprises a materialhaving a longitudinal wave sonic speed of 4,000 m/s or less.
 11. Theultrasonic sealing apparatus according to claim 10, wherein the materialcomprises a copper alloy.
 12. The ultrasonic sealing apparatus accordingto claim 11, wherein the copper alloy comprises phosphorous bronze. 13.The ultrasonic sealing apparatus according to claim 2, wherein theconverter has a screw portion to be fixed to one of the horn and thefixture using a screw connection.
 14. The ultrasonic sealing apparatusaccording to claim 1, further comprising a control means for controllingthe converters to produce a uniform and strong seal at the sealing face.15. The ultrasonic sealing apparatus according, to claim 4, wherein thescrew connection is a screw comprises a stud bolt.
 16. The ultrasonicsealing apparatus according to claim 1, wherein the sealing face is asealing face having a ridge in the longitudinal direction of the sealingface successively or intermittently.
 17. The ultrasonic sealingapparatus according to claim 1, wherein the frequency ranges from 20 KHzto 60 KHz.
 18. The ultrasonic sealing apparatus according to claim 17,wherein the frequency is 40 KHz.
 19. An ultrasonic sealing devicecomprising a plurality of ultrasonic apparatuses each according toclaim
 1. 20. A transverse sealing apparatus comprising in combinationthe ultrasonic sealing apparatus according to claim 1 and a sealing jawto which the ultrasonic sealing apparatus is fixed with a driving meansfor driving the sealing jaw.
 21. The transverse sealing apparatusaccording to claim 20, wherein the sealing jaw includes a damper memberfor the horn.
 22. The ultrasonic sealing apparatus according to claim 6,wherein the screw connection comprises a stud bolt.
 23. The ultrasonicsealing apparatus according to claim 13, wherein the screw connectioncomprises a stud bolt.